Generally, a water-soluble metal-processing agent such as a water-soluble cutting oil agent and a water-soluble grinding oil agent is produced by appropriately mixing components such as a mineral oil, a fatty oil, a fatty acid, a fatty acid ester, an extreme-pressure additive, a surfactant, a defoaming agent, a metal anticorrosive, an antioxidant, an antiseptic agent and an antifungal agent, according to a purpose. The water-soluble metal-processing agent is typically diluted 10 to 100 fold with a diluent such as water, for use. The thus-diluted water-soluble metal-processing agent is called “coolant”.
The coolant is required to exhibit excellent performance related to cutting and grinding properties such as improvement in finishing surface accuracy and extension of the lifetime of a tool (hereinafter referred to as “primary performance”), and to a working property and the like (hereinafter referred to as “secondary performance”). The above-mentioned secondary performance includes, for example, good rust resistance, slow deterioration and easy maintenance, harmlessness to the human body, low foaming tendency, and less unpleasant odor.
The water-soluble metal-processing agent and the coolant contain many ingredients which are nourishment sources suitable for a microbial such as a bacterium, a yeast fungus and a filamentous fungus. While the water-soluble metal-processing agent and the coolant are used, a microbial sometimes enters the water-soluble metal-processing agent and the coolant from dilution water, a workpiece, air and the like, and is proliferated therein. The entrance and proliferation of the microbial cause a problem that the water-soluble metal-processing agent and the coolant are putrefied. Development of the rotting of the coolant leads to not only deterioration of work environment but also pipe clogging in the circulation system, reduction in the machining efficiency, and the like. In order to prevent such reduction in the performance due to putrefaction, the water-soluble metal-processing agent and the coolant are supplied and replaced as required. However, if the water-soluble metal-processing agent and the coolant are supplied and replaced with higher frequencies, it is disadvantageous in terms of management of oil agents and cost. Therefore, it is very important to prevent deterioration of the water-soluble metal-processing agent and the coolant due to a microbial.
Hitherto, various kinds of fungicides and antiseptic agents are used to prevent the rotting of the water-soluble metal-processing agent and the coolant. For example, it is well known to add an antiseptic agent and a fungicide such as a formaldehyde-releasing type compound and a phenolic compound to the water-soluble metal-processing agent.
In addition, in order to address the above-mentioned problems, hitherto, a water-soluble metal-processing agent containing a variety of amine compound has been developed. Patent Document 1 discloses a water-soluble metal-processing agent in which dicyclohexylamine and/or cyclohexylamine are/is compounded with m-xylenediamine and/or 1,3-bis(aminomethyl)cyclohexane in a specific ratio. Patent Document 2 discloses a water-soluble metal-processing agent that contains an alkylenediamine having an alkylene group with 2 to 12 carbon atoms. Patent Document 3 discloses a water-soluble metal-processing agent containing N-substituted dialkyldiamine. Patent Document 4 discloses a water-soluble metal-processing agent containing an ethylene oxide adduct or propylene oxide adduct of meta- or ortho-xylenediamine, an ethylene oxide adduct or propylene oxide adduct of 1,3-bis-(aminomethyl)cyclohexylamine, and an ethylene oxide adduct or propylene oxide adduct of 1,4-bis-(aminomethyl)cyclohexylamine.
Since the water-soluble metal-processing agent is typically diluted with water for use, the agent is required to have an excellent rust preventing property for a machine and a workpiece. Particularly, as mentioned above, it is known that the rust preventing property is rapidly lowered as deterioration of the water-soluble metal-processing agent and the coolant due to a microbial is developed. In order to address such a problem, hitherto, a water-soluble metal-processing agent containing an anti-rust agent is used. Patent Document 5 discloses an anti-rust lubricating oil containing an acidic anti-rust agent such as a carboxylic acid and an acid scavenger such as N,N,N′,N′-tetraalkyl 1,8-naphthylenediamine.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. JP-A H05-279688
[Patent Document 2] Japanese Unexamined Patent Application Publication No. JP-A H02-228394
[Patent Document 3] Japanese Unexamined Patent Application Publication No. JP-A S60-49094
[Patent Document 4] Japanese Unexamined Patent Application Publication No. JP-A H09-316482
[Patent Document 5] Japanese Unexamined Patent Application Publication No. JP-A 2003-522216